As far as the main comic series and particularly multipart stories go, a majority of the ones since Reflections are pretty bad, though most of the one-shots tend to be fine to pretty good, as are the first few comics of the run
Micro series, unfortunately the ones featuring the mane six(save for Rarity and Pinkie) are bad to downright terrible, but the ones featuring others(Spike, Celestia, CMC and Luna) are great
Friends Forever is probably my favorite line, focusing….mostly on oddball pairings. Aside from the first comic which is pretty bad and the period where they focused on some shitty original characters for a few comics, it’s mostly consistent
Fiendship, unfortunately the Sombra and Tirek ones are the only ones worth talking about
The multiple side series they had after words I haven’t read but I heard they’re fine to good
Most of the comics focusing on EQG are really bad except for March Radness which is actually really good
The Holiday issues are mostly fine, except for the EQG one which is generally considered one of the worst comics of the run. Best one was probably the one after it
The annuals are average save for the Power Ponies one which I found pretty fun
20/20 was adorable
Deviations was pretty weak but it could have been worse honestly
Both the Transformers crossovers were great(second one was the better of the two imo due to having more interesting pair-ups and having the Mane Six+Spike be Micromasters). The G1 MLP crossover so far has been really bad unfortunately
Sorry it’s not detailed enough but it’s late right now